Effects of TPT on human monocyte–derived DCs. (A-B) Human monocytes were cultured with 50 ng/mL of GM-CSF and 50 ng/mL of IL-4 (G4 medium). After 24 hours, the medium was replaced with fresh G4 medium in the presence or absence of desired concentrations of TPT (0.5 nM-10 nM). At day 7 of incubation, cells were thoroughly washed, and the medium was supplemented with 10 ng/mL LPS. Forty-eight hours later, supernatants were collected for cytokine measurement and cells were labeled with the FITC–anti-CD83 mAb and analyzed by FACS. Data shown are summarized from 3 separate experiments (means ± SD). (A) Percent inhibition of CD83 expression and (B) IL-12_p70 production by LPS-stimulated DCs. (C) Effect of TPT on apoptosis of DCs. Human monocytes were cultured for 7 days with G4 medium in the presence of TPT (D2-7, 0.5-10 nM) or medium alone. The percentage of apoptotic cells was determined by FACS analysis using Annexin V/7-AAD staining. The data are representative of at least 5 separate experiments with cells derived from different donors. Numbers indicate percentage of cells present in corresponding quadrants.